1. Field of the Invention
The present invention relates to a mobile machine for grinding the surface of a floor, with particular utility of use on concrete floors.
2. Description of the Prior Art
For many years a need has existed for resurfacing concrete floors. That is, concrete floors that have once been surfaced are often ultimately resurfaced. In order to resurface a concrete floor it is often necessary, and certainly desirable, to remove remnants of the old surfacing material. For example, the paint on concrete floor surfaces with time often becomes chipped and the floors themselves become pitted. Before repainting or otherwise applying a new surface to the floor, it is highly advisable to remove the old paint.
Linoleum and other floor surfacing that is secured by adhesive to a floor often becomes cracked and broken with time. Individual tiles or even sections of sheets of floor finishing materials that are secured by adhesives to the floor often become loose over a period of time. In order to resurface the floor, it is necessary to remove the remnants remaining of the old surfacing material, as well as the hardened adhesive that once held the original material to the floor.
A variety of scraping, grinding, and blasting machines have been utilized to refinish floor surfaces. For example, hand-manipulated, electrically powered grinding machines are sometime used for this purpose. Such hand grinding machines typically have abrasive grinding blades or pads about seven inches in diameter. An operator must laboriously move the device across the floor surface from a kneeling position in order to remove old paint or old adhesive material. Due to the small surface area that can be ground or sanded at any particular time, the use of hand-manipulated grinders is extremely time consuming.
Also, the operator must manipulate the device from a stooped position, or more typically while resting on hands and knees. This is an extremely uncomfortable and tiring position in which to work. Furthermore, operation of hand-manipulated machines in this manner requires the operator's face to be positioned close to the surface area of the floor being ground. This subjects the operator to inhalation at close quarters of a large amount of ground floor surfacing particulate matter, grit, and dust. This aggravates the operator's discomfort, and additionally creates a health hazard to the machine operator.
There has been a considerable need for larger machines that have larger grinding pads or blades. Such machines can be constructed in the approximate size and shape of a power lawnmower, and can be manipulated by an operator from a standing position. These larger, wheeled floor grinding machines can cover a much larger floor area within a given time, and are much easier to operate than hand-manipulated grinders. However, the use of a mobile, wheeled floor grinding machine pushed using an operator handle is often impractical due to the considerable danger that high speed rotation of such a large blade or pad presents. For example, the high speed rotation of a thirty inch diameter blade presents a considerable safety hazard. If the blade strikes a hard object the wrong way, it can shatter and send broken portions of the blade flying with dangerous and even deadly effect.
Power consumption for such a machine, the size of the machine itself, and the cost of blades which may be utilized with such a machines are other factors that dictate against the use of a machine constructed with such a large grinding element. Thus, although the need for a large floor grinding machine that can be operated from a standing position has existed for many years, conventional devices of this type have been simply too dangerous or too expensive to gain significant commercial acceptance.